Advances in the characterization of industrial minerals
The use of minerals by man is as old as the human race. In fact the advancement of human civilization has been intimately associated with the exploitation of raw materials. It is not by chance that the distinction of the main historical eras is based on the type of raw materials used. Hence the passage from the Paleolithic and Neolithic Age to the Bronze Age is characterized by the introduction of basic metals, mainly copper, zinc and tin, to human activities and the Iron Age was marked by the introduction of iron. Since then the use of metals has increased and culminated in the industrial revolution in the mid-eighteenth century which marked the onset of the industrial age in the western world. However, during the past 50 years, although metals were equally important to western economies as they had been previously, the amount of metals extracted annually in western countries has decreased significantly and metal mining activity shifted mainly to third world countries (in Africa, South America, Asia) and Australia, due to economic and environmental constraints. At the same time the role of industrial minerals has become increasingly important for the western economies and today, in developed EU countries, the production of industrial minerals has surpassed by far the production of metals. In some EU countries, metal mining activities have stopped completely. The importance of industrial minerals is expected to increase further in the future.
Particle Size and Shape Characterization: Current Technology and Practice
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Published:January 01, 2010
Abstract
In the minerals industries, there is a frequent requirement to work with fine particulate matter, in the forms of powders, suspensions and granulates. The analysis and description of these particulates is an essential part of their processing and end-use; in particular, the characterization of their size distribution and morphology is useful in predicting behaviour in key mineral processes, such as comminution, sedimentation, filtration, flotation, calcination or granulation. For many industrial mineral applications, particle size and shape are also key to the end-function, such as in abrasives (such as sandpaper) or paint additives (such as matting aids). In this chapter, a particle’s size and the size distributions of a particle population are defined, and the prevalent methods and mechanisms of measuring size are discussed. The strengths and weaknesses of inferring distributions from images, light scattering patterns, sedimentation rates, and cytometric counts are weighed, and advice given on which methods may best suit one’s circumstances. In addition, image-analysis methods, which give size but also shape indicators, are described briefly.